Ultra Low Sulfur Diesel Revisited

It has been almost three years since the EPA has gone to ULSD (Ultra Low Sulfur Diesel) fuel and mandated major changes to on-highway engines to meet 2007 standards. Here is a quick refresher course on what has taken place.

With the new fuel comes some changes. For motor coach owners, that means some necessary adjustments in even some of the most basic routine maintenance procedures.

The good news is that you can make some of these changes across the entire spectrum of your preventative maintenance program and reap efficiency benefits. For instance: By upgrading your entire fleet to newer grades of oil and diesel, you won't have to bother with stocking an additional line of oil, buying a new set of fuel storage tanks, or worrying about adding the wrong lubricant to your new fleet.

The new ULSD fuel is mandatory for use in the engines equipped with DPFs (Diesel Particulate Filters), as is the higher-quality API-rating "CJ-4" engine oil. As with all other API rating changes, the newer oil is better than the previous "CG" or "CH" oils you are already using, so you can make the changeover with no problems.

ULSD has so far proven itself to be trouble free, with no appreciable loss of power, as many feared at first. It has been available in the market since late 2006, and availability is spreading. Using it throughout your fleet will simplify refueling and help the environment as well. On older engines, you may see a change in fuel mileage.

Dash Primer

For customers who own or are considering the purchase of coaches equipped with 2007 EPA compliant engines, there are a few new dash lights for your drivers and maintenance personnel to become familiar with, depending on the exact engine package you are running.


M.I.L.: Malfunction Indicator Lamp (DDEC only) lights to alert the driver that attention to the emission control components of the system is required. Controlled by the onboard engine computer, it refers ONLY to the emission-related parts of the system.

REGENERATION: Alerts the driver that DPF regeneration is required. Regeneration is a new required periodic maintenance procedure that will have to be added to your scheduled maintenance. For more information on regeneration, please click here.

HIGH EXHAUST TEMPERATURE: The HET light alerts the driver to a high-temperature condition of the exhaust system, and generally occurs below approximately 5 MPH.

Find more detailed explanations of system operations in the recently released service bulletins for the 2007 EPA engines. These should be added to your Maintenance Manuals:

  • SRB 2959D D Series CUMMINS engine configuration
  • SRB 2963E D Series CAT engine configuration
  • SRB 2964E D Series DETROIT engine configuration
  • SRB 2965C E / J DETROIT engine configuration
  • SRB 2966D E / J CAT engine configuration
  • SRB 2969C E / J CUMMINS engine configuration

FUEL SYSTEM: With all the different fuel choices such as ULSD, biodiesel, or low sulphur, it is strongly recommended that the fuel filters be changed at the manufacturer's recommended intervals. See section 10 of the MCI maintenance manual for more details if you are among those customers who are using biodiesel, as boidiesel can shorten fuel filter life.

For more information, see MCI Service Bulletins 2947, 2993 and 2996. And as always, you can learn more by calling the MCI Technical Call Center at 800-241-2947 or by participating in MCI's technical tune-ups or online webinars.

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